DE4221343C1 - Pyrotechnic material disposal - by controlled combustion and waste gas cleaning - Google Patents

Abstract

A pyrotechnic material disposal process involves (a) subjecting the material to controlled combustion, opt. allowing post-reaction of the slag and passing the waste gas thrugh a high temp. region in which the gas is heated at at least 1200 deg.C for a certain time to decompose any organic components; (b) cooling the resulting waste gas to below 400 deg.C; (c) cleaning the waste gas by a dry process, which the gas is passed through a coarse particle separator and then a fine dust filter, and/or by a wet process, in which the gas is passed through a rotary scrubber and then one or more absorption units; and (d) discharging the cleaned gas as waste air. USE/ADVANTAGE - The process is useful for disposal of old flares, trace munition, propellant charges, rocket propellants and/or smoke generators. It allows safe disposal without causing pollution and simultaneously recovers valuable materials and energy.

Description

The invention relates to a method for working up pyrotechnic material and a suitable device.

Pyrotechnic ammunition, such as illuminants, flare ammunition, Propellant charges, e.g. B. for missiles due to expiry of Shelf life is no longer operational, must be disposed of. A safe mechanical separation of the active mass is because of the pyrotechnic potential and the high Strength of the active mass not or only disproportionately high effort possible.

Luminous elements usually consist of a container that usually made of metal, preferably aluminum is an ignition charge and the active mass. The active mass sets a light metal powder as an energy supplier, a Oxidizing agent that can release oxygen, an organic Binder for mechanical consolidation of the batch and possibly color intensifiers together. Usually will Magnesium used as light metal powder, as others are considered upcoming metals either toxicologically or are too expensive. Nitrates are generally used as oxidizing agents, especially sodium nitrate, used, in exceptional cases chlorates or perchlorates are also used. As organic binders, polymers are used. As a color enhancer are halogen-containing compounds, in particular metal salts containing fluorine or chlorine. At the Burning off the luminous bodies therefore predominantly results in metal oxides, such as magnesium oxide, sodium oxide and aluminum oxide, nitrogen and nitrogen oxides and carbon oxides and, if appropriate  Hydrogen halide. Propellant charges consist essentially of Nitrocellulose.

DE-B 41 06 615 describes a process for working up chlorinated hydrocarbons containing mists or Fog effects known. These active masses are in such Processed that the zinc and aluminum compounds contained therein can be recovered and recycled. This procedure concerns special processing steps for the chlorinated hydrocarbons contained in the active compounds. Furthermore, DE-A 40 37 919 describes a method for Disposal of propellants from ammunition known at which crushed the propellant with the addition of water and then burned with a special fluidized bed combustion will.

It is an object of the invention to provide a method with the pyrotechnic material, in particular filament and propellant charges, which can be disposed of safely can be carried out and in which no harmful substances be discharged into the environment.

This task is solved with a processing method of pyrotechnic material, which is characterized by that he

• I. The pyrotechnic material burns off in a controlled manner If necessary, slag can react further and the resulting Raw gas passes through a high temperature area in which the gas a temperature of at least over a predetermined period of time 1200 ° C to existing organic substances decompose;
• II. The raw gas produced during the combustion to a temperature cools below 400 ° C;
• III. clean the raw gas dry by first putting it in one Leads pre-separator, whereby coarse particles are separated,  and then through fine dust filters to fine particles Separating solids, and / or
• IV. The raw gas is cleaned wet, in which it is first cleaned by one Rotation washer conducts via one or more absorption units leads, and
• V. releases the clean gas as exhaust air.

The method according to the invention succeeds in pyrotechnic Process material continuously, without any harmful Step outward, recyclable materials won and the heat generated can be used sensibly. Pyrotechnic material in the sense of the invention understood pyrotechnic objects and / or pyrotechnic phrases.  

In the first stage of the process according to the invention, the pyrotechnic material burned down in a controlled manner. The burning down can be done continuously or discontinuously, wherein preferably the tracked in continuous operation Material from the material already in the reactor is ignited while in the batch process always one batch burns and then the next batch is fed and is ignited. Throughput and residence time are dependent of the material to be burned, the type of process and the used Reactor. In general, the residence time is Range from 10 seconds to 1 minute.

The combustion takes place in one or more combustion chambers. A reactor is used as the combustion chamber, which at the Combustion can withstand high temperatures and is to be loaded in a suitable manner. Either is preferred a tubular reactor or a reactor with lining is used. preferably a vertically arranged tube reactor is used Device for use made of high temperature resistant steel exists and is cooled with gas inside. This is done by air Tangential nozzles inserted and guided over tangential plates so that it runs along the wall of the tubular reactor and so that the steel jacket cools. In this way it is achieved that the reactor jacket gets a maximum of up to 400 ° C, which it does without Endures damage. Through the air flow through tangential nozzles becomes the hot temperature zone to a certain area defined narrowed down. It is achieved on the one hand that organic pollutants directly at the origin by the Burning of the pyrotechnic bodies is practically completely reduced and, on the other hand, that caking of material or abrasion on the inner wall is prevented.

In another embodiment, a reactor with brick lining used. This reactor represents a closed one pressure-resistant space, which is lined with fireproof material on the inside is and is preferably a trough reactor or rotary kiln.  Because the refractory material has temperatures of over 1500 endures up to 2000 ° c, it does not need to be cooled. At a preferred embodiment of the reactor with lining a mobile trough is provided below the combustion chamber absorbs melting material and sinking slag and can be emptied in batches.

One or more can be used for the process according to the invention the same or different reactors used simultaneously will. Is preferred when working up pyrotechnic Material in which predominantly alkaline compounds in the Raw gas escape, a tube reactor used while for Refurbishment of pyrotechnic material, the predominant releases acidic vapors, a well reactor is used.

After the controlled burning of the pyrotechnic material the resulting raw gas is passed through a high temperature range conducted in a predetermined period of time on a Temperature of at least 1200 ° C is kept to possibly to decompose still existing organic matter. If the raw gas reached a temperature of over 1200 ° C by combustion has, it is sufficient to the raw gas without auxiliary firing above the predetermined Keep period in the reaction area. this happens in one embodiment, for example, by looking for the reactor provides a sufficient height so that the residence time of the rising raw gas for complete reaction sufficient in the high temperature range. In another Embodiment in which the air is blown in tangentially, the raw gas (reaction gas) is directed upwards in a spiral and remains in the high temperature range for a sufficiently long time. If the raw gas is not hot enough, one becomes External heating source is provided to get the raw gas to the desired level Heat temperature. The period of reheating is measured depends on the proportion of organic compounds and can be dated Expert can be easily determined. Usually one is sufficient Period of 2 to 10 seconds. To the organic compounds  to decompose, a temperature of at least 1200 ° C is preferred at least 1500 ° C required.

The raw gas leaving the high temperature range is practically pointing only inorganic compounds, some of which are gaseous, partly in the form of tiny particles. Depending on the composition the raw gas is dry cleaned and / or Wet cleaning performed. Wet cleaning can be done before or after dry cleaning. It is preferred first the raw gas is cleaned dry and then, if necessary, subjected to wet cleaning as required. Because the gas that emerges from the high temperature range, a very high temperature has, it is at a temperature below 400 ° C. cooled, while at the same time the heat is used becomes. Process engineering can be used in various applications Cold air is added to the hot gas for cooling. Furthermore can utilize heat using known heat recovery techniques occur. An example of this is the connection to the heating circuit of a heating plant. The cooling of the Raw gas occurs depending on the subsequent treatment Temperatures below 400 ° C or preferably below 200 ° C.

The raw gas is cleaned dry and / or wet. For the dry cleaning should set the gas to preferably below 200 ° C be cooled, the more effective "de novo syntheses" of organic To prevent pollutants. In addition, they can usually Filters used for cleaning usually cannot withstand higher temperatures without damage.

For dry separation, the raw gas is first put into one Pre-separator in which coarse particles are separated. Coarse particles are particles with a size of have at least 10 µm. The separation of the coarse particles can be done in a manner known per se. Is preferred for Deposition a multi-cyclone is used. The type of in which  Multicyclone deposited particles depend on the processed one pyrotechnic material. For example Signal masses or filament burned, so there are Coarse particles that are deposited in the multicyclone predominantly made of magnesium and / or aluminum oxide. The in Multi-cyclone deposited oxides can be reused are fed.

The raw gas freed from the coarse particles by the pretreatment has cooled sufficiently, can then be separated small solid particles, d. H. Particles with a diameter of less than 10 µm, passed through a fine dust filter will. Fabric filters are preferred as fine dust filters used. In a preferred embodiment, a System with multiple filters used, part of The filter is loaded simultaneously and the other part of the Filter is cleaned of the deposited solid mixture. With the fine dust filters, the raw gas can reach a solid content of 10 mg / m³ can be cleaned. That from the fine dust filters escaping gas now has a temperature of approx. 100 ° C and can if there are no gaseous impurities contains more, can be discharged directly as exhaust air. Show the gas gaseous contaminants, especially halogen-containing ones Compounds or nitrogen oxides, so it becomes after dry cleaning subjected to wet cleaning. When working up of signal and luminous active bodies, the gas is usually like this purely that wet cleaning is no longer necessary.

Instead of dry cleaning the gas, wet cleaning can be used be performed. This is useful if the gas is predominant gaseous impurities such as halogen compounds and Contains nitrogen oxides and less alkali and alkaline earth oxides. The Wet cleaning can also be done before or preferably after the dry cleaning can be done.  

If the raw gas is wet cleaned as the first cleaning step, so the raw gas is preferably first in a heat exchanger unit cooled to a temperature below 140 ° C. The raw gas cooled in the heat exchanger or that dry cleaned raw gas is then placed in a washing device directed to the wet scrubbing of the raw gas. Devices of this type are known to the person skilled in the art. This is preferred for wet washing Raw gas first passed through a venturi unit so the gas to cool far that its temperature is below the boiling point of water. Then it is placed in a rotary washer headed. After the rotary washing unit, the Gas scrubbing in a known manner with one or more absorption units. Packed or tray columns are preferred for this purpose used, depending on the loading of the gas with suitable Washing liquids are loaded. To these columns If necessary, additional filter units can be connected e.g. B. equipped with catalysts or carbon absorption filters are. The one emerging from the absorption unit (s) very pure gas is discharged as exhaust air.

To ensure that no Raw gas that is not fully cleaned is released into the environment the entire system can escape during operation driven in negative pressure. This takes place in a manner known per se Way, for example by using a suction fan.

The method according to the invention can be varied to the conditions the burning of various pyrotechnic materials surrender. So can the individual The stages of the process are connected in series as required will. If, for example, signal and luminous materials are burned off, which predominantly produce particulate oxides, the raw gas is preferred after cooling via pre-separators and fine dust filter and is then sufficiently pure to to be drained into the environment. Become pyrotechnic Bodies worked up, in which a high proportion of gaseous  Contamination occurs, the raw gas is preferred by Wet washing and piping cleaned by absorption units. Contains the gas also contains solids, so it can wet scrubbing with pre-separators and fine dust filters be performed. In any case, the procedure is carried out that the gas has only so small proportions of solids and gaseous compounds that it is on delivery the environment meets existing emission limit values.

Another object of the invention is a device for Refurbishment of pyrotechnic material that is labeled is controlled by (A) one or more reactor (s) Burning pyrotechnic material; (B) a heat exchanger unit for cooling the raw gas to a temperature of below 400 ° C, (C) a pre-separator for the separation of coarse particles; (D) one or more fine dust filters; (E) one Washing device for wet washing the raw gas and (F) one or several absorption unit (s), the individual components (A) to (F) with each other as required can be connected.

The device according to the invention is modular Concept suitable for processing different types of pyrotechnic Material such as B. signal and light ammunition, Propellant charges, rocket propellants, smoke agents and colored smoke. Depending on the type and physical state of the controlled Burning-off connections can cause individual Components or all components of the device according to the invention be connected to each other sequentially. In a preferred embodiment, as used in particular for Processing of signal and light ammunition is suitable, components (A), (B), (C) and (D) are connected in series. In another preferred embodiment, like them especially for processing fog active substances, propellant charges and rocket propellant is suitable, the components (A), (B), (E) and (F) connected in series. Arises at  controlled burning a very heterogeneous system that both gaseous contaminants and tiny particles contains, the components (A) to (F) are preferably connected in series. For the most economical processing possible component (B) is used in all cases, because on in this way the energy generated during combustion is obtained and can be brought to a sensible utilization.

The device according to the invention will now be explained in more detail with reference to FIGS. 1 and 2.

Fig. 1 shows a device that is particularly suitable for processing signal and light ammunition. It has a tubular reactor 1 , in which the signal and luminous elements are burned off in a controlled manner. The tubular reactor 1 is a reactor made of temperature-resistant steel without an inner lining. The signal and luminous elements are fed to the tubular reactor via a discontinuous feed device 2 . Furthermore, fresh air is fed to the tubular reactor 3 via a line 3 via tangential nozzles 5 . The raw gas produced during the combustion is kept at 1200 ° C. for at least two seconds and then fed via line 7 into the heat exchanger unit 9 . The hot gas heats water fed into the heat exchanger, which can be fed into the hot water or heating circuit of a heating plant. The gas leaves the heat exchanger unit 9 via line 11 and is fed into a multi-cyclone 13 , where coarse particles are separated. The Grobpartikal can be collected in reservoirs 14 via a rotary valve 12 batches. From the multicyclone, the gas is passed into fine dust filter 15 (A, B, C, D), where fine dust particles are separated. The fine dust filters are cleaned from time to time, with separated solids being discharged via the discharge screw 16 and collected in storage containers 18 . The clean gas is then discharged from the fine dust filters 15 into the environment via line 17 .

FIG. 2 shows a further preferred embodiment, in which a tubular reactor 101 or a trough reactor 102 can optionally be used for the controlled burning off of the pyrotechnic material. The pyrotechnic material to be burned can be fed to the tubular reactor 101 via a discontinuous feed device. When using the trough reactor 102 , the material is fed continuously via the hopper 104 . Both reactors 101 , 102 are connected to the heat exchanger system 109 via lines 107 and 108, respectively. The gas is fed into the heat exchanger system as in the embodiment described in FIG. 1 and then via line 111 into the multicyclone 113 and from there into the fine dust filter 115 (A, B, C, D). Parts with the same function as in FIG. 1 are designated by the same reference number in FIG. 2, increased by the number 100 . The gas emerging from the fine dust filters 115 can still be cleaned wet in this embodiment. For this purpose, it is fed via a line 119 into a rotary washing unit 121 and from there fed to one or more absorption unit (s) 123 , which are provided with suitable washing templates 124 . The washing templates 124 can be worked up discontinuously. For this purpose, a neutralizing solution from the neutralization template 126 is pumped into the liquid present in the washing templates via a pump 125 . The neutralized solution is then drained into the buffer pool 127 . After wet cleaning, the gas has such a low level of impurities that it can be released into the environment via line 128 .

In addition to the two systems described, the individual Elements of the device according to the invention in any Connect in a row, depending on the one used pyrotechnic material and the resulting composition of the flue gas.

According to the invention, a method and an apparatus for Provided to different types of pyrotechnic  Process material safely and without polluting the environment, while gaining valuable material and energy at the same time will.

Claims (14)

1. Process for working up pyrotechnic material, characterized in that

• I. the pyrotechnic material burns off in a controlled manner, the slag is optionally reacted and the raw gas is passed through a high-temperature range in which the gas is exposed to a temperature of at least 1200 ° C for a predetermined period in order to decompose any organic substances still present;
• II. The raw gas produced during the combustion cools to a temperature below 400 ° C;
• III. the raw gas is dry cleaned by first passing it into a pre-separator, whereby coarse particles are separated, and then passing the raw gas over fine dust filters to separate fine particles and / or
• IV. Wet cleaning the raw gas by first passing it through a rotary scrubber and then passing it through one or more absorption units, and
• V. releases the cleaned gas as exhaust air.

2. The method according to claim 1, characterized in that as pyrotechnic material signal body, light ammunition, Propellant charges, rocket propellants and / or mist bodies worked up will. 3. The method according to claim 1, characterized in that the pyrotechnic material in a well reactor, the one mobile trough below the combustion chamber to accommodate has melting material and sinking slags, is burned down.   4. The method according to claim 1 or 2, characterized in that the pyrotechnic material in a tubular reactor, the Air supplied via tangential nozzles and via tangential plates is directed so that it sweeps along the wall of the tubular reactor and cools the steel jacket, burns it down. 5. The method according to any one of the preceding claims, characterized characterized that reaction chamber and gas treatment devices be kept under negative pressure. 6. The method according to any one of the preceding claims, characterized characterized in that in stage (I) the raw gas to a Temperature of up to 2000 ° C is heated. 7. The method according to any one of the preceding claims, characterized characterized in that in stage (II) the raw gas for the Dry cleaning cooled to a temperature below 200 ° C becomes. 8. The method according to any one of the preceding claims, characterized in that in stage (III) the raw gas, the direct the wet cleaning is fed to a temperature below 140 ° C is cooled. 9. The method according to any one of the preceding claims, characterized characterized in that in stage (III) as a pre-separator Multicyclone is used. 10. The method according to any one of the preceding claims, characterized characterized in that in stage (IV) the rotary washer a Venturi washer is connected upstream. 11. The method according to any one of the preceding claims, characterized characterized in that in stage (IV) as an absorption unit Packed columns or tray columns can be used.   12. Device for processing pyrotechnic material, characterized by

• A) one or more reactors for the controlled burning of pyrotechnic material;
• B) a heat exchanger unit for cooling the raw gas to a temperature below 400 ° C;
• C) a pre-separator for the separation of coarse particles;
• D) one or more fine dust filters;
• E) a washing device for wet washing the raw gas and
• F) one or more absorption unit (s), the individual components (A) to (F) being connected to one another in any manner as required.

13. The apparatus according to claim 12, characterized in that components (A), (B), (C) and (D) are consecutive are interconnected. 14. The apparatus according to claim 12, characterized in that components (A), (B), (E) and (F) are consecutive are connected.